A primary technique for strengthening and toning abdominal muscles, such as the rectus abdominous, is the abdominal crunch or sit-up. To perform a crunch, a person lies on his back and bends his knees by drawing his heels in towards his buttocks. He then curls his upper body into a concave position so the head, neck and shoulders are slightly elevated off the floor and the elbows are contacting the knees. In this position, the rectus abdominous is contracted. He returns to the starting position, thereby relaxing the muscle, and repeats the sequence of steps for a desired number of repetitions.
Abdominal crunches can cause many physical ailments. As the number of repetitions increases, not only the rectus abdominous but also the neck muscles weaken (because the neck muscles must support the head). A person can attempt to compensate for the weakened rectus abdominous by jerking his head and upper back to help complete the repetitions. The jerking motion can further weaken the neck muscles and possibly lead to neck and/or back injuries. Although he can place his hands behind his neck to support the neck, he will have a tendency to pull up on his arms to help complete repetitions, which neutralizes the benefits of supporting the neck with the hands.
A number of devices have been designed to reduce the stress on the neck experienced during crunches. In one device disclosed in U.S. Pat. No. 5,458,549 ("the '549 patent"), the exercise device has an elongated sheet of flexible, resilient, cushioned material and a substantially rigid support panel attached to the backside, which supports the head, neck and upper back of the user during crunches. The flat device extends from the head region to the buttocks region (to permit the lower end of the device to be held in position during the crunches). This device has a number of problems. The length of the device restricts the user's freedom of movement in crunches, especially in crunches that require the upper body to rotate from side to side. The substantially rigid support panel limits the ability of the device to conform to the lordotic and kyphotic curves, thereby causing user discomfort.
Another device is disclosed in U.S. Pat. No. 5,169,372 ("the '372 patent"). The device has a head-receiving portion that is placed against the head of the user. A base of the device is placed against the back of the user's neck to support the user's head and neck and partially support the weight of the user's head during abdominal crunches. The device includes grooves that function as handles for the user. Like the device of the '549 patent, this device has drawbacks. Because the base rests on the occipital bone (i.e., the base of the skull), the device fails to eliminate neck and back strains during crunches.